Force-activated thermal battery for use in a wellbore

Abstract

A thermal battery positioned in a wellbore can be force activated by a device. The device can include a body coupled to a thermal battery positioned in a wellbore. The body can include a piston retained at a first position in an inner area of the body. The piston can move from the first position to a second position in response to a force applied to the body. The thermal battery can be activated by moving the piston to the second position.

What is claimed is: 
     
       1. A device comprising:
 a body coupleable to a thermal battery and positionable in a wellbore, the body comprising a piston retained at a first position in an inner area of the body, the piston being moveable from the first position to a second position in response to a force applied to the body and for activating the thermal battery by moving to the second position, wherein the thermal battery is a first thermal battery, and wherein the body is removable from the wellbore separate from the first thermal battery and reusable with a second thermal battery. 
 
     
     
       2. The device of  claim 1 , wherein the body further comprises shear pins for retaining the piston at the first position and for shearing in response to the force exceeding a threshold value to allow the piston to move to the second position. 
     
     
       3. The device of  claim 2 , wherein the body further comprises a firing pin coupled to a surface of the piston for contacting a primer as the piston moves to the second position to ignite pyrotechnics that activate the thermal battery in response to contact with the firing pin. 
     
     
       4. The device of  claim 3 , wherein the body further comprises a primer having a piezoelectric material for responding to contact with the firing pin by generating an electrical signal to ignite the pyrotechnics. 
     
     
       5. The device of  claim 2 , wherein the body further comprises a magnet coupled to a surface of the piston for generating an electrical signal by passing through a coil as the piston moves to the second position, the electrical signal being transmittable for igniting pyrotechnics to activate the thermal battery. 
     
     
       6. The device of  claim 1 , wherein the force is a change in a pressure in the wellbore caused by a pump at a surface of the wellbore. 
     
     
       7. The device of  claim 1 , wherein the body is coupleable to a tubular string and the force is caused at least in part by a drop bar moving through the tubular string. 
     
     
       8. The device of  claim 1 , wherein the body further comprises an electrical power-conditioning module communicatively coupleable between the first thermal battery and a tool powered by electrical power from the first thermal battery for regulating an output of the first thermal battery. 
     
     
       9. A system comprising:
 a tool positionable in a wellbore; 
 a thermal battery positionable in the wellbore and communicatively coupleable to the tool for providing power to the tool in response to being heated above a threshold temperature; and 
 a body positionable in the wellbore and coupleable to the thermal battery for responding to a force by heating the thermal battery above the threshold temperature, and wherein the thermal battery is a first thermal battery, and wherein the body is removable from the wellbore separate from the first thermal battery and reusable with a second thermal battery. 
 
     
     
       10. The system of  claim 9 , wherein the body comprises a piston retained at a first position in an inner area of the body by shear pins, the shear pins for shearing in response to the force exceeding a threshold value to allow the piston to move to a second position. 
     
     
       11. The system of  claim 10 , wherein the body further comprises a firing pin coupled to a surface of the piston for contacting a primer in response to the piston moving to the second position to ignite pyrotechnics for heating the thermal battery to a temperature above the threshold temperature. 
     
     
       12. The system of  claim 10 , wherein the body further comprises a magnet coupled to a surface of the piston for generating an electrical signal by passing through a coil in response to the piston moving to the second position, the electrical signal being transmittable for igniting pyrotechnics to heat the thermal battery to a temperature above the threshold temperature. 
     
     
       13. The system of  claim 10 , further comprising a pump positionable at a surface of the wellbore for generating the force by changing a pressure in the wellbore. 
     
     
       14. The system of  claim 10 , further comprising a tubular string coupleable to the body, wherein the force is at least partially generatable by a drop bar traversing the tubular string. 
     
     
       15. The system of  claim 9 , further comprising an electrical power-conditioning module communicatively coupleable between the thermal battery and the tool for regulating an output of the thermal battery. 
     
     
       16. A method comprising:
 moving a piston retained in a body positioned in a wellbore from a first position in an inner area of the body to a second position in the inner area of the body in response to a force being applied to the piston; 
 generating an electrical signal by moving a magnet coupled to the piston through a coil coupled to the body as a result of the piston moving to the second position; 
 igniting pyrotechnics coupled to a thermal battery using the electrical signal; 
 heating a thermal battery positioned in the wellbore with the pyrotechnics based on the piston moving to the second position; and 
 activating the thermal battery coupled to the body based on heating the thermal battery above a threshold temperature. 
 
     
     
       17. The method of  claim 16 , wherein moving the piston comprises:
 shearing a shear pin retaining the piston at the first position in response to the force exceeding a threshold value. 
 
     
     
       18. The method of  claim 16 , wherein the thermal battery is a first thermal battery and the force is a first force, the method further comprising:
 generating the first force by using a pump positioned at a surface of the wellbore to change a pressure in the wellbore; 
 powering a first tool in the wellbore with the first thermal battery; 
 removing the body from the wellbore separate from the first thermal battery; and 
 positioning the body in the wellbore to activate a second thermal battery in response to a second force being applied to the piston.